Apparatuses and methods for monitoring health of probing u-bump cluster using current divider

ABSTRACT

An apparatus includes an input probe configured to be placed on a first cluster of u-bumps disposed on a semiconductor die, output probes configured to be respectively placed on multiple clusters of u-bumps disposed on the semiconductor die, the multiple clusters being separately connected to the first cluster. The apparatus further includes a space transformer and printed circuit board (PCB) portion including a current source configured to supply a current to the input probe placed on the first cluster, resistors having a same resistance and being connected to ground, and tester channels at which voltages are respectively measured, the tester channels being respectively connected to ends of the output probes respectively placed on the multiple clusters and being respectively connected to the resistors. The apparatus further includes a processor configured to determine whether the input probe is properly aligned with the first cluster, based on the measured voltages.

BACKGROUND

Fine pitch assembly with 2.5-dimensional (2.5D) and 3-dimensional (3D)die stacking architecture may require solder-to-solder u-bump connectionbetween top and bottom dies. 2.5D and 3D die assembly may allow diedisaggregation, which provides the flexibility of assembling differentchiplets from multiple sources and multiple technologies on the samebase die.

To provide enough power during sort/test probing, u-bumps may need to beprobed in clusters. Probes may be typically aligned with the u-bumps,using an optical alignment referred to as probe-to-pad alignment (PTPA).Alignment of a probe to a center of a cluster may be key to deliveroptimal power and signal and to prevent probing-induced damage, thusimproving a yield of a product.

However, except for gross issues, misalignments may be typicallydiscovered after manual inspection under a microscope for known issues,which may require time, equipment and human resources. The misalignmentsmay even go unnoticed and be discovered only after packaging, which mayresult in a huge yield loss. The misalignments may also be discoveredafter the fact, and may not be monitored in-situ.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameparts throughout the different views. The drawings are not necessarilyto scale, emphasis instead generally being placed upon illustrating thepresent disclosure. The dimensions of the various features or elementsmay be arbitrarily principles expanded or reduced for clarity. In thefollowing description, various aspects of the present disclosure aredescribed with reference to the following drawings, in which:

FIG. 1A is a plan view of a semiconductor device to be stacked;

FIG. 1B is a cross-sectional circuit diagram of probing the u-bumpcluster, along a line of FIG. 1A, according to aspects of the presentdisclosure;

FIG. 2A is a plan view of a semiconductor device to be stacked,according to aspects of the present disclosure;

FIG. 2B is a plan view circuit diagram of an apparatus for monitoringhealth of probing a u-bump cluster included in the semiconductor deviceof FIG. 2A;

FIG. 2C is a cross-sectional circuit diagram of the apparatus of FIG.2B;

FIG. 3 is a flow diagram of a method of monitoring health of probing au-bump cluster, using a current divider, according to aspects of thepresent disclosure; and

FIG. 4 is a block diagram of a testing device for performing the methodof FIG. 3 .

DETAILED DESCRIPTION

The following detailed description refers to the accompanying drawingsthat show, by way of illustration, specific details and aspects in whichthe present disclosure may be practiced. These aspects are described insufficient detail to enable those skilled in the art to practice thepresent disclosure. Various aspects are provided for devices, andvarious aspects are provided for methods. It will be understood that thebasic properties of the devices also hold for the methods and viceversa. Other aspects may be utilized and structural, and logical changesmay be made without departing from the scope of the present disclosure.The various aspects are not necessarily mutually exclusive, as someaspects can be combined with one or more other aspects to form newaspects.

The present disclosure relates to apparatuses and methods for monitoringhealth of probing a u-bump cluster, using a current divider.

A present apparatus may include an input probe configured to be placedon a first cluster of u-bumps disposed on a semiconductor die, outputprobes configured to be respectively placed on multiple clusters ofu-bumps disposed on the semiconductor die, the multiple clusters beingseparately connected to the first cluster. The apparatus may furtherinclude a space transformer and printed circuit board (PCB) portionincluding a current source configured to supply a current to the inputprobe placed on the first cluster, resistors having a same resistanceand being connected to ground, and tester channels at which voltages arerespectively measured, the tester channels being respectively connectedto ends of the output probes respectively placed on the multipleclusters and being respectively connected to the resistors. Theapparatus may further include a processor configured to determinewhether the input probe is properly aligned with the first cluster,based on the measured voltages.

In another aspect, a method pursuant to the present disclosure mayinclude controlling an input probe to be placed on a first cluster ofu-bumps disposed on a semiconductor die, controlling output probes to berespectively placed on multiple clusters of u-bumps disposed on thesemiconductor die, the multiple clusters being separately connected tothe first cluster, and controlling a current source to supply a currentto the input probe placed on the first cluster. The method may furtherinclude measuring voltages respectively at tester channels respectivelyconnected to ends of the output probes respectively placed on themultiple clusters, and respectively connected to resistors having a sameresistance and being connected to ground, and determining whether theinput probe is properly aligned with the first cluster, based on themeasured voltages.

In yet another aspect, a non-transitory computer-readable medium mayinclude instructions, which, if executed by a processor, cause theprocessor to control an input probe to be placed on a first cluster ofu-bumps disposed on a semiconductor die, control output probes to berespectively placed on multiple clusters of u-bumps disposed on thesemiconductor die, the multiple clusters being separately connected tothe first cluster, and control a current source to supply a current tothe input probe placed on the first cluster. The instructions, which, ifexecuted by the processor, may further cause the processor to measurevoltages respectively at tester channels respectively connected to endsof the output probes respectively placed on the multiple clusters, andrespectively connected to resistors having a same resistance and beingconnected to ground, and determine whether the input probe is properlyaligned with the first cluster, based on the measured voltages.

The above-detailed aspects may use direct current (DC) through eachu-bump in a u-bump cluster as a proxy to a probe-to-bump overlap area,when a probe lands on the u-bump cluster, to test the u-bump cluster.The overlap area may then be used to determine a health of probing theu-bump cluster, e.g., whether the probe is properly aligned with theu-bump cluster.

Further, each individual u-bump in the u-bump cluster may be routed todifferent nearby u-bump clusters connected in series to known resistors.A known current may be forced through the probe to the u-bump cluster inquestion. A voltage drop across each of the known resistors may beutilized to calculate a current through each u-bump in the u-bumpcluster and hence the probe-to-bump overlap area.

Advantageously, such u-bump cluster probing may enable 2.5D and 3D diestacking with a die sort. Without this architecture, a dedicated sortpad may be needed, which may consume u-bump real estate and reduce apackage power delivery. Also, there may be a chance that misalignedprobing damages a u-bump and results in a poor yield.

FIG. 1A is a plan view of a semiconductor device 100 to be stacked.

Referring to FIG. 1A, the semiconductor device 100 includes asemiconductor die 110, and a u-bump cluster 120 or micro-bump clusterdisposed on the semiconductor die 110. The u-bump cluster 120 mayinclude u-bumps 120A, 120B, 120C, 120D, 120E, . . . and 120N. Each ofthe u-bumps 120A-120N may include a Cu pillar, Cu and solder (e.g.,SnAg, SnInAg, and/or SnAgCu), Cu, Ni and solder, and/or Cu, Ni, Cu andsolder.

FIG. 1B is a cross-sectional circuit diagram of probing the u-bumpcluster 120, along a line 130 of FIG. 1A, according to aspects of thepresent disclosure.

Referring to FIG. 1B, the semiconductor device 100 further includes aconductive metal interconnect 140 under and connected to the u-bumps120A-120N included in the u-bump cluster 120. Although not shown, theconductive metal interconnect 140 may connect all of the u-bumps120A-120N to each other.

The probing of the u-bump cluster 120 is performed by a probing device150, which includes a space transformer and printed circuit board (PCB)portion 160 and one probe 170. The space transformer and PCB portion 160is a multi-layer stack structure that performs signal routing for theprobe 170, and includes a current source 180 outputting a current I.

The probing of the u-bump cluster 120 includes placing portions of theprobe 170 respectively on multiple u-bumps (e.g., the u-bumps 120A-120N)of the same net, to test the u-bumps. The probe 170 may include, forexample, alloys of Cu, Ag, Au, Pd, Rd, Be, and/or Ni, e.g., a highconductivity material having high mechanical strength and chemicalresistance. The net may be a particular power, ground, or signal, e.g.,the current I. In this example, the current source 180 is connected toeach of the portions of the probe 170 so that each of the portions ofthe probe 170 respectively transfers the current Ito the u-bumps120A-120N.

An alignment of the probe 170 to each of the u-bumps 120A-120N maychange from one touchdown to another touchdown, due to alignment marginsof the probe 170. Accordingly, a contact area at which the probe 170contacts or overlaps each of the u-bumps 120A-120N may also change. Theu-bumps 120A-120N may contact the probe 170 at contact areas 190A, 190B,190C, 190D, 190E, . . . and 190N, respectively, which may be differentin size.

If the total current I is forced through the probe 170, depending uponthe contact areas 190A-190N, each of the u-bumps 120A-120N may receiveand carry a different part of the total current I. The u-bumps 120A-120Nmay respectively receive and carry currents I₁, I₂, I₃, I₄, I₅, . . .and I_(N). The following continuity relation for the total current I mayhold:=I ₁ +I ₂ +I ₃ +I ₄ +I ₅ +. . . I _(N).   (1).

A contact resistance between the probe 170 and each of the u-bumps120A-120N is inversely proportional to the contact area 190A, 190B,190C, 190D, 190E, . . . or 190N between the probe 170 and a respectiveone of the u-bumps 120A-120N. That is, a larger contact area results ina smaller contact resistance and a larger current, provided remainingcircuit elements are identical.

Thus, by knowing the currents I₁-I_(N) respectively through theindividual u-bumps 120A-120N, information about the contact areas190A-190N between the probe 170 and the u-bumps 120A-120N may bedetermined. Based on this determined information, a misalignment (e.g.,lack of health) of the probe 170 with any of the u-bumps 120A-120N maybe advantageously detected.

To know the currents I₁-I_(N) respectively through the u-bumps120A-120N, a current divider may be used, in which each of the u-bumps120A-120N is connected in series to ground through a respective portionof the conductive metal interconnect 140 and a respective one ofresistors having an identical resistance R, as conceptually shown inFIG. 1B. A voltage across each of the resistors may be measured using arespective one of tester channels, e.g., output nodes.

If V₁, V₂, V₃, V₄, V₅, . . . and V_(N) are voltages respectively acrossthe identical resistors connected to the u-bumps 120A-120N, then thecorresponding currents I₁-I_(N) may be found using the followingrelations:I ₁ =V ₁ /R;I ₂ =V ₂ /R;. . .I _(N) =V _(N) /R.   (2)

FIG. 2A is a plan view of a semiconductor device 200 to be stacked,according to aspects of the present disclosure. FIG. 2B is a plan viewcircuit diagram of an apparatus 250 for monitoring health of probing au-bump cluster 220 included in the semiconductor device 200 of FIG. 2A.FIG. 2C is a cross-sectional circuit diagram of the apparatus 250 ofFIG. 2B.

Referring to FIG. 2A, the semiconductor device 200 includes asemiconductor die 210, the u-bump cluster 220 disposed on thesemiconductor die 210, u-bump clusters 222, 224, 226 and 228 alsodisposed on the semiconductor die 210, and conductive metalinterconnects 230 and 240 disposed on and/or in the semiconductor die210.

The u-bump cluster 220 includes 4 u-bumps belonging to the same netcorresponding to a low current power supply. Accordingly, the u-bumpcluster 220 may be referred to as LC+. Each of the u-bumps included inthe u-bump cluster 220 is connected to a u-bump included in a respectiveone of u-bump clusters 222, 224, 226 and 228 by a respective one of theconductive metal interconnects 230.

Each of the u-bump clusters 222, 224, 226 and 228 includes 4 u-bumpsthat are daisy chained together by respective ones of the conductivemetal interconnects 240. The u-bump clusters 222, 224, 226 and 228 mayrespectively be referred to as a tester channel 1 (TC1), a testerchannel 2 (TC2), a tester channel 3 (TC3) and a tester channel 4 (TC4).Each of the u-bump clusters 220, 222, 224, 226 and 228 may be probed bya respective one of 5 probes to test the u-bump cluster 220, as follows.

Referring to FIGS. 2B and 2C, the apparatus 250 includes a spacetransformer and PCB portion 260, an input probe 270 and output probes280. The space transformer and PCB portion 260 is a multi-layer stackstructure that performs signal routing for the input probe 270 and theoutput probes 280, and includes a current source 290, conductive metalinterconnects 292, tester channels 294 and resistors 296.

The apparatus 250 is a current divider for monitoring the health of theprobing of the u-bump cluster 220 (LC+) for testing the u-bump cluster220. The current source 290 outputs a current I of, e.g., 200milliamperes (mA) ISVM (current source voltage measure). The currentsource 290 is connected to the input probe 270 so that the input probe270 transfers the current I to the u-bump cluster 220.

Each of the u-bumps included in the u-bump cluster 220 is connected tothe u-bumps included in a respective one of u-bump clusters 222, 224,226 and 228 (TC1-TC4) by a respective one of the conductive metalinterconnects 230. Accordingly, the total current I is divided intocurrents I₁-I₄ that are respectively transferred through the conductivemetal interconnects 230 and 240, the u-bump clusters 222, 224, 226 and228 and the output probes 280 and then back to the space transformer andPCB portion 260.

Each of the u-bump clusters 222, 224, 226 and 228 and their respectiveoutput probes 280 (e.g., distal ends of the output probes 280) areconnected in series to ground through a respective one of the conductivemetal interconnects 292 and a respective one of the resistors 296 havingan identical resistance R, e.g., of 10 ohms. A voltage across each ofthe resistors 296 may be measured using a respective one of the testerchannels 294. As a result, for the u-bump clusters 222, 224, 226 and228, respective voltages V₁-V₄ across the resistors 296 may be measuredusing the tester channels 294.

If the input probe 270 is equally in contact with all of the u-bumpsincluded in the u-bump cluster 220, each of the u-bumps would receive 50mA from the input probe 270, hence the voltage measured at each of thetester channels 294 would be 0.5 volts (V). This is an ideal case inwhich the contact between the input probe 270 and each of the u-bumpsincluded in the u-bump cluster 220 is all good. If the voltage measuredat each of the tester channels 294 is not 0.5 V, then the input probe270 may not be landing with equal overlap on each of the u-bumpsincluded in the u-bump cluster 220. This is due to misalignment as theinput probe 270 is designed to land evenly on each of the u-bumpsincluded in the u-bump cluster 220. This electric feedback of thevoltage measured at each of the tester channels 294 may be in-situ, anda corrective action (e.g., realignment of the input probe 270 on theu-bump cluster 220) may advantageously be taken to obtain a desiredresult in which the voltage measured at each of the tester channels 294is 0.5 V.

In another example, if the input probe 270 is equally in contact withall of the u- bumps included in the u-bump cluster 220, except for thoseat edges and/or corners of the u-bump cluster 220 at which the contactwith the input probe 270 may be lesser in area, each of the u-bumps mayreceive, from the input probe 270, a predetermined expected value ofcurrent, among the total current, e.g., 200 mA. In this example, centeru-bumps included in the u-bump cluster 220 may receive 50 mA from theinput probe 270, while edge u-bumps included in the u-bump cluster 220may receive 40 mA from the input probe 270. Hence the ideal voltagemeasured at each of the tester channels 294 corresponding to the centeru-bumps would be 0.5 V, while the ideal voltage measured at each of thetester channels 294 corresponding to the edge u-bumps would be 0.4 V.

Although each of the u-bump clusters 220, 222, 224, 226 and 228 is shownhere to include 4 u-bumps, each of the u-bump clusters 220, 222, 224,226 and 228 may include any number of u-bumps. Similarly, although 5probes are used herein, N+1 probes may be used, N being a number ofu-bumps in a u-bump cluster to be tested. In particular, one input probemay probe the u-bump cluster to be tested, and N output probes mayrespectively probe N u-bump clusters respectively connected to the Nu-bumps in the u-bump cluster to be tested.

FIG. 3 is a flow diagram of a method 300 of monitoring health of probinga u-bump cluster, using a current divider, according to aspects of thepresent disclosure.

Referring to FIG. 3 , in operation 310, the method 300 includescontrolling an input probe to be placed on a first cluster of u-bumpsdisposed on a semiconductor die, and controlling output probes to berespectively placed on multiple clusters of u-bumps disposed on thesemiconductor die, the multiple clusters being separately connected tothe first cluster. For example, the input and output probes may becontrolled via a robotic positioning system.

In operation 320, the method 300 includes controlling a current sourceto supply a current to the input probe placed on the first cluster. Forexample, the current source may be included in a space transformer andPCB portion.

In operation 330, the method 300 includes measuring voltagesrespectively at tester channels respectively connected to ends of theoutput probes respectively placed on the multiple clusters, andrespectively connected to resistors having a same resistance and beingconnected to ground. For example, the voltages may be measured via avoltmeter, and the tester channels and resistors may be included in thespace transformer and PCB portion.

In operation 340, the method 300 includes determining whether themeasured voltages respectively correspond to predetermined values. Basedon the measured voltages being determined to respectively correspond tothe predetermined values, the method 300 continues in operation 350.Otherwise, the method 300 continues in operation 360. The measuredvoltages may be determined to respectively correspond to thepredetermined values when the measured voltages are determined to beequal to each other.

In operation 350, the method 300 includes determining that the inputprobe is properly aligned with the first cluster, and the method 300ends.

In operation 360, the method 300 includes determining that the inputprobe is improperly aligned with the first cluster, and method 300returns to operation 310 for realignment of the input probe on the firstcluster.

The methods and sequence of steps presented above are intended to beexamples for monitoring health of probing a u-bump cluster, using acurrent divider, according to aspects of the present disclosure. It willbe apparent to those ordinary skilled practitioners that the foregoingprocess operations may be modified without departing from the spirit ofthe present disclosure.

FIG. 4 is a block diagram of a testing device 400 for performing themethod of FIG. 3 .

Referring to FIG. 4 , the testing device 400 may include a memory 405, aprocessor 410, an input/output (I/O) interface 415 and a bus 420.

The memory 405 may include a volatile and/or non-volatile memory. Thememory 405 can store information, such as one or more of commands, data,programs (one or more instructions), applications, etc., which arerelated to at least one other component of the testing device 400 andfor driving and controlling the testing device 400. For example,commands and/or data may formulate an operating system (OS). Informationstored in the memory 405 can be executed by the processor 410. Thememory 405 may store the information that is executed by the processor410 to perform functions and operations described with respect to FIGS.1A-3 above.

The processor 410 may include one or more of a central processing unit(CPU), a graphics processor unit (GPU), an accelerated processing unit(APU), a many integrated core (MIC), a field-programmable gate array(FPGA), and/or a digital signal processor (DSP). The processor 410 canbe a general-purpose controller that performs control of any one or anycombination of the other components of the testing device 400, and/orperforms an operation or data processing relating to communication. Theprocessor 410 may execute one or more programs stored in the memory 405.

The I/O interface 415 may serve as a hardware and/or software interfacethat can, for example, transfer commands and/or data between a user,other external devices and/or other components of the testing device400. The I/O interface 415 can further set up communication between thetesting device 400 and an external testing device. The I/O interface 415may be connected to a network through wireless or wired communicationarchitecture to communicate with the external testing device. The I/Ointerface 415 may be a wired or wireless transceiver or any othercomponent for transmitting and receiving signals.

The bus 420 may include a circuit for connecting the components 405, 410and 415 with one another. The bus 420 functions as a communicationsystem for transferring data between the components 405, 410 and 415 orbetween testing devices.

To more readily understand and put into practical effect the presentapparatuses and methods, particular aspects will now be described by wayof examples. For the sake of brevity, duplicate descriptions of featuresand properties may be omitted.

EXAMPLES

Example 1 provides an apparatus including an input probe configured tobe placed on a first cluster of u-bumps disposed on a semiconductor die,output probes configured to be respectively placed on multiple clustersof u-bumps disposed on the semiconductor die, the multiple clustersbeing separately connected to the first cluster. The apparatus furtherincludes a space transformer and printed circuit board (PCB) portionincluding a current source configured to supply a current to the inputprobe placed on the first cluster, resistors having a same resistanceand being connected to ground, and tester channels at which voltages arerespectively measured, the tester channels being respectively connectedto ends of the output probes respectively placed on the multipleclusters and being respectively connected to the resistors. Theapparatus further includes a processor configured to determine whetherthe input probe is properly aligned with the first cluster, based on themeasured voltages.

Example 2 may include the apparatus of example 1 and/or any otherexample disclosed herein, for which the processor may be furtherconfigured to determine whether the measured voltages respectivelycorrespond to predetermined values.

Example 3 may include the apparatus of example 2 and/or any otherexample disclosed herein, for which the processor may be furtherconfigured to, based on the measured voltages being determined torespectively correspond to the predetermined values, determine that theinput probe is properly aligned with the first cluster.

Example 4 may include the apparatus of example 2 and/or any otherexample disclosed herein, for which the processor may be furtherconfigured to, based on the measured voltages being determined to notrespectively correspond to the predetermined values, determine that theinput probe is improperly aligned with the first cluster.

Example 5 may include the apparatus of example 2 and/or any otherexample disclosed herein, for which the processor may be furtherconfigured to, based on the measured voltages being determined to notrespectively correspond to the predetermined values, control the inputprobe to be realigned on the first cluster.

Example 6 may include the apparatus of example 2 and/or any otherexample disclosed herein, for which the measured voltages may bedetermined to respectively correspond to the predetermined values whenthe measured voltages are determined to be equal to each other.

Example 7 may include the apparatus of example 1 and/or any otherexample disclosed herein, for which a first one of the multiple clustersmay be connected to a first u-bump of the first cluster, and a secondone of the multiple clusters may be connected to a second u-bump of thefirst cluster.

Example 8 provides a method including controlling an input probe to beplaced on a first cluster of u-bumps disposed on a semiconductor die,controlling output probes to be respectively placed on multiple clustersof u-bumps disposed on the semiconductor die, the multiple clustersbeing separately connected to the first cluster, and controlling acurrent source to supply a current to the input probe placed on thefirst cluster. The method further includes measuring voltagesrespectively at tester channels respectively connected to ends of theoutput probes respectively placed on the multiple clusters, andrespectively connected to resistors having a same resistance and beingconnected to ground, and determining whether the input probe is properlyaligned with the first cluster, based on the measured voltages.

Example 9 may include the method of example 8 and/or any other exampledisclosed herein, for which the determining whether the input probe isproperly aligned with the first cluster may include determining whetherthe measured voltages respectively correspond to predetermined values.

Example 10 may include the method of example 9 and/or any other exampledisclosed herein, for which the determining whether the input probe isproperly aligned with the first cluster may further include, based onthe measured voltages being determined to respectively correspond to thepredetermined values, determining that the input probe is properlyaligned with the first cluster.

Example 11 may include the method of example 9 and/or any other exampledisclosed herein, for which the determining whether the input probe isproperly aligned with the first cluster further may further include,based on the measured voltages being determined to not respectivelycorrespond to the predetermined values, determining that the input probeis improperly aligned with the first cluster.

Example 12 may include the method of example 9 and/or any other exampledisclosed herein, further including, based on the measured voltagesbeing determined to not respectively correspond to the predeterminedvalues, controlling the input probe to be realigned on the firstcluster.

Example 13 may include the method of example 9 and/or any other exampledisclosed herein, for which the measured voltages may be determined torespectively correspond to the predetermined values when the measuredvoltages are determined to be equal to each other.

Example 14 may include the method of example 8 and/or any other exampledisclosed herein, for which a first one of the multiple clusters may beconnected to a first u-bump of the first cluster, and a second one ofthe multiple clusters may be connected to a second u-bump of the firstcluster.

Example 15 provides a non-transitory computer-readable medium includinginstructions, which, if executed by a processor, cause the processor tocontrol an input probe to be placed on a first cluster of u-bumpsdisposed on a semiconductor die, control output probes to berespectively placed on multiple clusters of u-bumps disposed on thesemiconductor die, the multiple clusters being separately connected tothe first cluster, and control a current source to supply a current tothe input probe placed on the first cluster. The instructions, which, ifexecuted by the processor, further cause the processor to measurevoltages respectively at tester channels respectively connected to endsof the output probes respectively placed on the multiple clusters, andrespectively connected to resistors having a same resistance and beingconnected to ground, and determine whether the input probe is properlyaligned with the first cluster, based on the measured voltages.

Example 16 may include the non-transitory computer-readable medium ofexample 15 and/or any other example disclosed herein, for which theinstructions, which, if executed by the processor, may further cause theprocessor to determine whether the measured voltages respectivelycorrespond to predetermined values.

Example 17 may include the non-transitory computer-readable medium ofexample 16 and/or any other example disclosed herein, for which theinstructions, which, if executed by the processor, may further cause theprocessor to, based on the measured voltages being determined torespectively correspond to the predetermined values, determine that theinput probe is properly aligned with the first cluster.

Example 18 may include the non-transitory computer-readable medium ofexample 16 and/or any other example disclosed herein, for which theinstructions, which, if executed by the processor, may further cause theprocessor to, based on the measured voltages being determined to notrespectively correspond to the predetermined values, determine that theinput probe is improperly aligned with the first cluster.

Example 19 may include the non-transitory computer-readable medium ofexample 16 and/or any other example disclosed herein, for which theinstructions, which, if executed by the processor, may further cause theprocessor to, based on the measured voltages being determined to notrespectively correspond to the predetermined values, control the inputprobe to be realigned on the first cluster.

Example 20 may include the non-transitory computer-readable medium ofexample 16 and/or any other example disclosed herein, for which themeasured voltages may be determined to respectively correspond to thepredetermined values when the measured voltages are determined to beequal to each other.

Example 21 provides an apparatus including first controlling means forcontrolling an input probe to be placed on a first cluster of u-bumpsdisposed on a semiconductor die, and controlling output probes to berespectively placed on multiple clusters of u-bumps disposed on thesemiconductor die, the multiple clusters being separately connected tothe first cluster. The apparatus further includes second controllingmeans for controlling a current source to supply a current to the inputprobe placed on the first cluster, measuring means for measuringvoltages respectively at tester channels respectively connected to endsof the output probes respectively placed on the multiple clusters, andrespectively connected to resistors having a same resistance and beingconnected to ground, and determining means for determining whether theinput probe is properly aligned with the first cluster, based on themeasured voltages.

Example 22 may include the apparatus of example 21 and/or any otherexample disclosed herein, for which the determining means may further befor determining whether the measured voltages respectively correspond topredetermined values.

Example 23 may include the apparatus of example 22 and/or any otherexample disclosed herein, for which the determining means may further befor, based on the measured voltages being determined to respectivelycorrespond to the predetermined values, determining that the input probeis properly aligned with the first cluster.

Example 24 may include the apparatus of example 22 and/or any otherexample disclosed herein, for which the determining means may further befor, based on the measured voltages being determined to not respectivelycorrespond to the predetermined values, determining that the input probeis improperly aligned with the first cluster.

Example 25 may include the apparatus of example 22 and/or any otherexample disclosed herein, for which the first controlling means mayfurther be for, based on the measured voltages being determined to notrespectively correspond to the predetermined values, controlling theinput probe to be realigned on the first cluster.

It will be understood that any property described herein for a specificdevice may also hold for any device described herein. It will also beunderstood that any property described herein for a specific method mayhold for any of the methods described herein. Furthermore, it will beunderstood that for any device or method described herein, notnecessarily all the components or operations described will be enclosedin the device or method, but only some (but not all) components oroperations may be enclosed.

The term “comprising” shall be understood to have a broad meaningsimilar to the term “including” and will be understood to imply theinclusion of a stated integer or operation or group of integers oroperations but not the exclusion of any other integer or operation orgroup of integers or operations. This definition also applies tovariations on the term “comprising” such as “comprise” and “comprises”.

The term “coupled” (or “connected”) herein may be understood aselectrically coupled or as mechanically coupled, e.g., attached or fixedor attached, or just in contact without any fixation, and it will beunderstood that both direct coupling or indirect coupling (in otherwords: coupling without direct contact) may be provided.

The methods described herein may be performed and the various processingor computation units and the devices and computing entities describedherein may be implemented by one or more circuits. In an embodiment, a“circuit” may be understood as any kind of a logic implementing entity,which may be hardware, software, firmware, or any combination thereof.Thus, in an embodiment, a “circuit” may be a hard-wired logic circuit ora programmable logic circuit such as a programmable processor, e.g., amicroprocessor. A “circuit” may also be software being implemented orexecuted by a processor, e.g., any kind of computer program, e.g., acomputer program using a virtual machine code. Any other kind ofimplementation of the respective functions that are described herein mayalso be understood as a “circuit” in accordance with an alternativeembodiment.

While the present disclosure has been particularly shown and describedwith reference to specific aspects, it should be understood by thoseskilled in the art that various changes in form and detail may be madetherein without departing from the spirit and scope of the presentdisclosure as defined by the appended claims. The scope of the presentdisclosure is thus indicated by the appended claims and all changeswhich come within the meaning and range of equivalency of the claims aretherefore intended to be embraced.

What is claimed is:
 1. An apparatus comprising: an input probeconfigured to be placed on a first cluster of u-bumps disposed on asemiconductor die; output probes configured to be respectively placed onmultiple clusters of u-bumps disposed on the semiconductor die, themultiple clusters being separately connected to the first cluster; aspace transformer and printed circuit board (PCB) portion comprising: acurrent source configured to supply a current to the input probe placedon the first cluster; resistors having a same resistance and beingconnected to ground; and tester channels at which voltages arerespectively measured, the tester channels being respectively connectedto ends of the output probes respectively placed on the multipleclusters and being respectively connected to the resistors; and aprocessor configured to determine whether the input probe is properlyaligned with the first cluster, based on the measured voltages.
 2. Theapparatus of claim 1, wherein the processor is further configured todetermine whether the measured voltages respectively correspond topredetermined values.
 3. The apparatus of claim 2, wherein the processoris further configured to, based on the measured voltages beingdetermined to respectively correspond to the predetermined values,determine that the input probe is properly aligned with the firstcluster.
 4. The apparatus of claim 2, wherein the processor is furtherconfigured to, based on the measured voltages being determined to notrespectively correspond to the predetermined values, determine that theinput probe is improperly aligned with the first cluster.
 5. Theapparatus of claim 2, wherein the processor is further configured to,based on the measured voltages being determined to not respectivelycorrespond to the predetermined values, control the input probe to berealigned on the first cluster.
 6. The apparatus of claim 2, wherein themeasured voltages are determined to respectively correspond to thepredetermined values when the measured voltages are determined to beequal to each other.
 7. The apparatus of claim 1, wherein a first one ofthe multiple clusters is connected to a first u-bump of the firstcluster, and a second one of the multiple clusters is connected to asecond u-bump of the first cluster.
 8. A method comprising: controllingan input probe to be placed on a first cluster of u-bumps disposed on asemiconductor die; controlling output probes to be respectively placedon multiple clusters of u-bumps disposed on the semiconductor die, themultiple clusters being separately connected to the first cluster;controlling a current source to supply a current to the input probeplaced on the first cluster; measuring voltages respectively at testerchannels respectively connected to ends of the output probesrespectively placed on the multiple clusters, and respectively connectedto resistors having a same resistance and being connected to ground; anddetermining whether the input probe is properly aligned with the firstcluster, based on the measured voltages.
 9. The method of claim 8,wherein the determining whether the input probe is properly aligned withthe first cluster comprises determining whether the measured voltagesrespectively correspond to predetermined values.
 10. The method of claim9, wherein the determining whether the input probe is properly alignedwith the first cluster further comprises, based on the measured voltagesbeing determined to respectively correspond to the predetermined values,determining that the input probe is properly aligned with the firstcluster.
 11. The method of claim 9, wherein the determining whether theinput probe is properly aligned with the first cluster furthercomprises, based on the measured voltages being determined to notrespectively correspond to the predetermined values, determining thatthe input probe is improperly aligned with the first cluster.
 12. Themethod of claim 9, further comprising, based on the measured voltagesbeing determined to not respectively correspond to the predeterminedvalues, controlling the input probe to be realigned on the firstcluster.
 13. The method of claim 9, wherein the measured voltages aredetermined to respectively correspond to the predetermined values whenthe measured voltages are determined to be equal to each other.
 14. Themethod of claim 8, wherein a first one of the multiple clusters isconnected to a first u-bump of the first cluster, and a second one ofthe multiple clusters is connected to a second u-bump of the firstcluster.
 15. A non-transitory computer-readable medium comprisinginstructions, which, if executed by a processor, cause the processor to:control an input probe to be placed on a first cluster of u-bumpsdisposed on a semiconductor die; control output probes to berespectively placed on multiple clusters of u-bumps disposed on thesemiconductor die, the multiple clusters being separately connected tothe first cluster; control a current source to supply a current to theinput probe placed on the first cluster; measure voltages respectivelyat tester channels respectively connected to ends of the output probesrespectively placed on the multiple clusters, and respectively connectedto resistors having a same resistance and being connected to ground; anddetermine whether the input probe is properly aligned with the firstcluster, based on the measured voltages.
 16. The non-transitorycomputer-readable medium of claim 15, wherein the instructions, which,if executed by the processor, further cause the processor to determinewhether the measured voltages respectively correspond to predeterminedvalues.
 17. The non-transitory computer-readable medium of claim 16,wherein the instructions, which, if executed by the processor, furthercause the processor to, based on the measured voltages being determinedto respectively correspond to the predetermined values, determine thatthe input probe is properly aligned with the first cluster.
 18. Thenon-transitory computer-readable medium of claim 16, wherein theinstructions, which, if executed by the processor, further cause theprocessor to, based on the measured voltages being determined to notrespectively correspond to the predetermined values, determine that theinput probe is improperly aligned with the first cluster.
 19. Thenon-transitory computer-readable medium of claim 16, wherein theinstructions, which, if executed by the processor, further cause theprocessor to, based on the measured voltages being determined to notrespectively correspond to the predetermined values, control the inputprobe to be realigned on the first cluster.
 20. The non-transitorycomputer-readable medium of claim 16, wherein the measured voltages aredetermined to respectively correspond to the predetermined values whenthe measured voltages are determined to be equal to each other.